1. Field of the Invention
The present invention relates to an illuminated knob device for audio equipment of a motor vehicle or for the like.
2. Description of the Background Art
FIG. 2 is a sectional view of a conventional illuminated knob device disclosed in Unexamined Japan Utility Model Application No. 24232/91. The device includes an illuminated knob 11, the rotary shaft 12a of a variable resistor and switch 12, and a light emission diode 13. The knob 11 has a light guide portion 11a, a light bending portion 11b, and an outer luminous portion 11c, and is fitted on the rotary shaft 12a. The diode 13 is attached to the resistor and switch 12 mounted on a printed circuit board 14. Rays of light are emitted from the diode 13, transmitted through the light guide portion 11a, reflected by the light bending portion 11b, and irradiated upon the outer luminous portion 11c to illuminate it.
Since the illuminated knob 11 is rotated synchronously with the rotary shaft 12a, only one point can be illuminated in the outer luminous portion 11c. This is a problem. Since the light emission diode 13 is located in a fixed position, the luminance of the luminous portion 11c varies from rotation angle to rotation angle. This is also a problem.